Dynamo-electric machine



G.-A. PARSONS AND J. ROSEN.

DYNAMO ELECTRIC MACHINE. APPLICATION FILED FEB. 10, 1919.

PatentedSept. 27,1921.

INVENTORS.

Charles A. Parse/n23 B Y esse/ Rose r AIR-"AXES.

cnmansnnonmron PARSONS AND JESSEL nosnmoor NEWCASTLEUPON-TYNE,

ENGLAND; SAID ROSEN ASSIGNOR liO SAID PARSONS.

DYNAMIC-ELECTRIC MACHINE.

Application filedlebruary 10, 1919. Serial No. 276,121.

To all whom it may. concern:

Be 1t known that we, CHARLES ALGERNON PARSONS and Jnssnn RosnN, subjects of the King of Great Britain and Ireland, and both residing at Heaton \Vorks, Newcastle-upon- Tyne, in the. county of Northumberland, England, have invented certain new and useful Improvements in Dynamo-Electric Machines, of which the following is a specification.

Many dynamo electric machines arenow designed with laminated core conductors coupled to end connectors built up of solid copper strips. p This construction has great advantages since the solid cop-per strips are comparatively cheap and are also exceedingly strong and robust and better able to withstand the heavy stresses which are sometimes thrown upon them when the machine is accidentally short circuited. At present in the case of machines generating large currents the disadvantage of these large solid end connectors is the heating that oc-' curs where they join the laminated core conduct0rs,at which point some comparatively massive form of joint has hitherto been necessary; it is often found that the greatest heating takes place at these joints and-especially where solder is used-overheating at this point may be more serious than in other parts of the machine.

The object of the present invention is to overcome this difficulty.

A method which has been used in the case of heavy current machines having large conductors, to overcome the difficulty is to have several electrical circuits in parallel, each circuit carrying only a fraction of the current. The subdivision into separate circuits reduces the losses, but, the multiplication of electrical circuits through a machine has obvious disadvantages.

At the joint mentioned above, there are two sources of loss, (I) that due to the eddy currents, and (II) that due to the ohmic resistance across the solder or similar material between the core conductor and the end connector. This resistance may be termed the surface resistance of the joint. We have found that the substitution of a plurality of joints for the one joint has the effect of reducing these losses.

The n e ti n c ns s n s d i g the Specification of Letters Patent. Patented Sept. 1 921.

joints between the core conductors and the end connectors in dynamo electric machines having large conductors, thus providing two or more smaller joints. I

The invention further consists in the use of suchsubdivided joints in conjunction with end connectors also divided up into a plurality of strips or bars.

The invention further" consists in the use of one main strip which may be slit; into laminations by narrow saw cuts orit may be electrically welded or solderedto short laminations, each lamination serving to make one of the joints as before described. Referring to the accompanying .draw- 1ngs:- j c Figure 1 is a part section through the ar- ,matu re core of the dynamo electric machine showing the conductors projecting beyond the core.

Fig. 2 is an end view of the joints of one conductor in Fig. 1. a r

Fig. 3 shows an alternative method of making the joint.

Figs. 4 and 5 are end views of the joint in the case in which a solid end connector is employed.

Fig. 6 is a sectional end view of Fig. .1, showing the manner in which the end con nections are made.

Fig. 1 illustrates a part section of an al- I ternator armature with one conductor per slot and with the end connections E built into two layers L this being a standard arrangement.

The core conductor B is insulated from the core A by a tube H of suitable insulating material to withstand the full voltage of the alternator. This tube H extends beyond the core and the conductor on emerging therefrom is divided into. bundles C: for ease of workmanship the dividing up of the conductor B into bundles, at the ends, may be done before placing the conductor into position in the core A; in the present case the conductor ends are divided so as to form three joints 1) at each end of the conductor B, and three strips E in parallel form one end connector and together carry the full current. Each of the three bundles C formed from the main conductor B has the strip end connector fitted around it in the form 9f a loop J. The strip end connector as illustrated in Fig. 2 is thinned down at the loop to a lesser thickness than its thickness through its main length. An alternative arrangement is shown in Fig. 3 where the individual strip itself E is again subdivided into two parts so as to obtain the loop more readily as illustrated. By the methods illustrated in Figs. 2 and 3 the amountof metal in the joint is reduced to a minimum, without reducing unduly the mechan ical strength of the joint.

The joints may be insulated one from the other by a thin layer of insulation material F which may be carried around between the individual strips E; the insulation F can be very light, as there is no appreciable difference of electric potential between any of the joints at one end of the core conductor B or between the individual strips E of one end connector at any point throughout its length.

In the form shown in Fig. 4, the end connector M is solid throughout its length, and

is slit at the ends to form the laminations E.

In the modification shown in Fig. 5, separate laminations E are used and connected to the solid end connector M by any well known method suchas electrical welding or soldering. In both cases illustrated in Figs. 4 and 5 a loop is formed of each lamination E and the joints are made and insulated as described above.

Having now described our invention, what to secure by Letnectors in which, the ends of each conductor are divided into a number of parts and a separate joint made between each part and the end connector to which the conductor is .to be joined.

8. A dynamo electric machine having conductors made separately from the end connectors in which, the ends of each conductor and of each connector are divided into a like number. of parts and separate joints made between each part of the conductor and a corresponding part of the end connector.

4:. A dynamo electric machine as set forth in claim 3, in which the end connectors are built up of a number of strips corresponding in number to the parts into which the corresponding conductor is divided and a separate joint made betweeneach strip and one of the parts of the conductor.

In testimony whereof we have signed our namesto this specification.

CHARLES ALGERNON PARSONS. JESSEL ROSEN. 

